Patent Grant
9044973
1. Field of the Invention
The present invention relates to a technique for a sheet conveying apparatus usable with a printing apparatus.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 11-208923 discusses a printing apparatus that conveys a sheet by using a conveying mechanism including rollers. A sheet is nipped by a roller pair constituted by a conveyance roller and a driven roller, and is conveyed according to a rotation of the roller pair. The driven roller is divided into a plurality (three) of small rollers along the direction of the rotational axis thereof. The plurality of divided rollers is collectively pressed by using a single pressing unit, and the nip pressures thereof are changed as the sheet is transported forward.
The printing apparatus discussed in Japanese Patent Application Laid-Open No. 11-208923 is configured in such a manner that forces provided to change the nip pressures act on the plurality of divided driven rollers in a uniform way for all of them, and these forces cannot be adjusted individually.
One aspect of the present invention is directed to a sheet conveying apparatus and a printing apparatus capable of conveying a sheet at high accuracy regardless of a sheet that the printing apparatus uses.
According to an aspect of the present invention, a sheet conveying apparatus includes a conveyance roller, and a pinch roller configured to nip a sheet between the conveyance roller and the pinch roller. The pinch roller includes a first roller portion and a second roller portion adjacent to each other in a rotational axial direction thereof, and further includes a mechanism configured to change a difference between a pressing force that the first roller portion applies to the conveyance roller and a pressing force that the second roller portion applies to the conveyance roller.
According to an exemplary embodiment of the present invention, the difference between the respective pressing forces of the first roller portion and the second roller portion included in the pinch roller can be changed, so that a sheet conveying apparatus and a printing apparatus capable of conveying a sheet at high accuracy regardless of a sheet that the printing apparatus uses can be implemented.
Further features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention.
Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings.
A printing apparatus based on the inkjet printing method according to an exemplary embodiment of the present invention is a high-speed line printer using a long continuous sheet (a continuous sheet longer than a repeated print unit referred to as “one page” or “unit image” in a conveyance direction) and capable of performing both one-sided printing and two-sided printing. For example, this printing apparatus is suitable to the field of printing of a large number of sheets, for example, in a print lab.
The present exemplary embodiment can be widely applied to a printing apparatus that uses ink and has to dry the ink thereafter, such as a printer, a multifunction peripheral, a copying machine, a facsimile apparatus, and manufacturing apparatuses of various kinds of devices. Further, the present exemplary embodiment can be also applied to a printing apparatus that forms a latent image on a sheet coated with a photosensitive material by, for example, a laser, and performs printing by the liquid development method. Further, the present exemplary embodiment can be also applied to not only a sheet processing apparatus that performs printing processing, but also sheet processing apparatuses that perform various kinds of processing (for example, recording, processing, coating, irradiating, reading, and inspecting) on a sheet.
The sheet feeding unit 1 is a unit for holding and feeding a continuous sheet wound into a rolled shape. The sheet feeding unit 1 can contain two rolls R1 and R2, and is configured to selectively pull out one of them to feed it. The number of rolls that the sheet feeding unit 1 can contain is not limited to two, and the sheet feeding unit 1 can contain less than or greater than two rolls. Further, the present exemplary embodiment may use any continuous sheet which is not limited to a sheet wound into a rolled shape. For example, the present exemplary embodiment may use a continuous sheet which is perforated at each unit length and folded at each line of the perforation, and is then stacked in this state to be contained in the sheet feeding unit 1.
The decurling unit 2 is a unit for reducing a curl (warpage) of a sheet fed from the sheet feeding unit 1. The decurling unit 2 conveys a sheet while curving the sheet so as to provide a warpage in the opposite direction from a curl with use of two pinch rollers for one conveyance roller to thereby exert a decurling force to reduce the curl.
The skew correction unit 3 is a unit for correcting a skew state (inclination relative to an originally set forward direction) of a sheet transported from the decurling unit 2. The skew correction unit 3 corrects a skew state of a sheet by pressing the sheet edge of the side that is used as a basis of the correction against a guide member. A loop is formed at the sheet being conveyed at the skew correction unit 3.
The printing unit 4 is a sheet processing unit for forming an image by applying print processing onto a sheet being conveyed from above the sheet by print heads 14. In other words, the printing unit 4 is a processing unit for performing predetermined processing on a sheet. The printing unit 4 also includes a plurality of conveyance rollers for conveying a sheet. As the print heads 14, a plurality of print heads is arranged in parallel with one another along the conveyance direction. In the present exemplary embodiment, the printing apparatus includes seven line print heads corresponding to seven colors of cyan (C), magenta (M), yellow (Y), light cyan (LC), light magenta (LM), gray (G), and black (K). The number of colors and the number of print heads are not limited to seven. Further, as the inkjet printing method, the printing apparatus according to the present exemplary embodiment may employ, for example, the method using a heating element, a piezoelectric element, an electrostatic element, and a micro electric mechanical systems (MEMS) element. Ink of each color is supplied from an ink tank to the print head 14 through a corresponding ink tube.
The inspection unit 5 is a unit for optically reading an inspection example or image, which is printed onto a sheet at the printing unit 4, by a scanner to inspect, for example, a nozzle state of the print heads 14, a sheet conveyance state, and an image position, thereby determining whether an image is correctly printed. The scanner includes a charge coupled device (CCD) image sensor or a complementary metal-oxide semiconductor (CMOS) image sensor.
The cutter unit 6 is a unit including a cutter for cutting a printed sheet into pieces each having a predetermined length. The cutter cuts a sheet at a margin area between images formed on the sheet and at the rear of an image printed last.
The information recording unit 7 is a unit for recording print information (unique information) such as a serial number and/or a print date of a print output on an unprinted area of a cut sheet. This recording is performed by printing a character and a code by, for example, the inkjet printing method or the thermal transfer method.
The drying unit 8 is a unit for heating a sheet printed at the printing unit 4 to dry the provided ink in a short time. In the drying unit 8, hot air is applied to at least the bottom surface of a sheet passing through, thereby drying the surface with ink provided thereon. The drying method here is not limited to applying hot air. The drying unit 8 may dry a sheet surface by emitting electromagnetic waves (for example, ultraviolet ray or infrared ray) onto the sheet surface.
The sheet conveyance path from the sheet feeding unit 1 to the drying unit 8 described above is referred to as a “first path”. The first path is shaped to have a U-turn between the printing unit 4 and the drying unit 8, and the cutter unit 6 is located at some position along the U-turn shape.
The reversing unit 9 is a unit for temporarily taking up a continuous sheet with an image printed on the front surface thereof to turn over the sheet during two-sided printing. The reversing unit 9 is disposed at some position along a path (loop path referred to as a “second path”) from the drying unit 8 to the printing unit 4 via the decurling unit 2 so as to supply a sheet transferred from the drying unit 8 to the printing unit 4 again. The reversing unit 9 includes a take-up rotator (drum) configured to rotate to take up a sheet. An uncut continuous sheet, after printing of the front surface, is temporarily taken up by the take-up rotator. After the take-up is finished, the take-up rotator is rotated in the reverse direction so that the taken up sheet is sent in reverse order of the order at the time of the take-up to be supplied to the decurling unit 2, and is then sent to the printing unit 4. Since this sheet is turned upside down, the printing unit 4 can print an image on the back surface of the sheet. Assuming that the sheet feeding unit 1 is a first sheet feeding unit, the reversing unit 9 can be considered as a second sheet feeding unit. More specific details of the two-sided printing operation will be described below.
The discharge conveyance unit 10 is a unit for conveying a sheet cut by the cutter unit 6 and dried by the drying unit 8 to transfer the sheet to the sorter unit 11. The discharge conveyance unit 10 is disposed at a path (referred to as a “third path”) different from the second path where the reversing unit 9 is disposed. A path switching mechanism having a movable flapper is disposed at a path branching position (referred to as a “discharge branching position”) so as to selectively guide a sheet conveyed along the first path to any one of the second path and the third path.
The sheet discharge unit 12 including the sorter unit 11 is disposed at a position at the side of the sheet feeding unit 1 and at the terminal of the third path. The sorter unit 11 is a unit for sorting printed sheets into groups as necessary. The sorted sheets are discharged onto a plurality of trays included in the sheet discharge unit 12. In this way, the third path is laid out so as to extend below the sheet feeding unit 1 to discharge a sheet to the opposite side of the sheet feeding unit 1 from the printing unit 4 and the drying unit 8.
In this way, the units from the sheet feeding unit 1 to the drying unit 8 are disposed along the first path in this order. The path beyond the drying unit 8 is branched into the second path and the third path. The second path includes the reversing unit 9 at a position along it, and is merged with the first path at a position beyond the reversing unit 9. The third path includes the sheet discharge unit 12 at the terminal thereof.
The control unit 13 is a unit in charge of control of the respective units of the entire printing apparatus. The control unit 13 includes a central processing unit (CPU), a storage device, a controller (control unit) including various kinds of control units, an external interface, and an operation unit 15 where a user provides an input and receives an output. The operation of the printing apparatus is controlled based on an instruction from the controller or a host apparatus 16 such as a host computer connected to the controller via the external interface.
A dedicated processing unit is provided to a unit that is required to perform data processing at a high speed. The image processing unit 207 applies image processing to print data handled by the printing apparatus. The image processing unit 207 converts the color space (for example, Luminance/Chroma Blue/Chroma Red (YCbCr)) of input image data into a commonly-used Red/Green/Blue (RGB) color space (for example, the standard RGB (sRGB) color space). Further, the image processing unit 207 applies various kinds of image processing such as a resolution conversion, an image analysis, and an image correction to image data as necessary. The print data acquired by these kinds of image processing is stored in the RAM 203 or the HDD 204. The engine control unit 208 drives and controls the print heads 14 of the printing unit 4 according to print data based on a control command received from, for example, the CPU 201. Further, the engine control unit 208 also controls the conveying mechanisms of the respective units in the printing apparatus. The individual unit control unit 209 is a sub controller for individually controlling the respective units of the sheet feeding unit 1, the decurling unit 2, the skew correction unit 3, the inspection unit 5, the cutter unit 6, the information recording unit 7, the drying unit 8, the reversing unit 9, the discharge conveyance unit 10, the sorter unit 11, and the sheet discharge unit 12. The individual control unit 209 controls the operations of the respective units based on an instruction from the CPU 201. The external interface 205 is an interface (I/F) for enabling a connection of the controller to a host apparatus 211, and is a local I/F or a network I/F. The constituent elements mentioned above are connected to one another through a system bus 210.
The host apparatus 16 is an apparatus that serves as a supply source of image data that the printing apparatus is ordered to print. The host apparatus 16 may be either a general-purpose computer or a dedicated computer. Alternatively, the host apparatus 16 may be a dedicated image device such as an image capture device including an image reader unit, a digital camera, and a photo storage medium. In a case where the host apparatus 16 is a computer, an operating system (OS), application software for generating image data, and a printer driver for the printing apparatus are installed in a storage apparatus of the computer.
Next, a basic operation performed during printing will be described. The printing apparatus operates in different manners in the one-sided printing mode and the two-sided printing mode, and, therefore, both the one-sided printing mode and the two-sided printing mode will be described, respectively.
First, the one-sided printing mode will be described. The thick solid line in
Next, the two-sided printing mode will be described. The printing apparatus executes a front (first)-surface print sequence, and consecutively executes a back (second)-surface print sequence. In the front-surface print sequence performed first, the respective units from the sheet feeding unit 1 to the inspection unit 5 operate in the same manner as the operations for the above-described one-sided printing. The cutter unit 6 does not cut the sheet at this time, and, therefore, the sheet is conveyed to the drying unit 8 as a continuous sheet. After the ink on the surface is dried at the drying unit 8, the sheet is guided to the path (second path) leading to the reversing unit 9, not to the path (third path) leading to the discharge conveyance unit 10. In the second path, the sheet is taken up by the take-up drum of the reversing unit 9, which rotates in the forward direction (the counterclockwise direction as viewed in
After the above-described front-surface printing sequence, the operation is switched to the back-surface printing sequence. The take-up drum of the reversing unit 9 starts to rotate in the opposite direction (the clockwise direction as viewed in
The first roller pair includes a conveyance roller 101 provided with a rotation driving force, and a pinch roller 102 driven to rotate. Further, an adjustment mechanism 110 is provided so as to individually variably adjust a nip pressure which the pinch roller 102 applies to the conveyance roller 101. The second roller pair includes a conveyance roller 103 provided with a rotation driving force, and a pinch roller 104 driven to rotate. The conveyance forces with which the first roller pair and the second roller pair convey a sheet are set so as to satisfy the relationship expressed by the following mathematical expression (1).
first roller pair>second roller pair (1)
The conveyance force of a roller pair is determined based on the nip pressure of the pinch roller. This is because, as a nip pressure is increased, this increase makes it difficult to generate a slip between a sheet and the surface of the roller. A nip pressure is determined based on the spring pressure of a spring that presses a pinch roller against a conveyance roller. When this relationship is satisfied, the first roller pair has maximum dominance over the sheet conveyance accuracy.
The conveyance speeds of the respective roller pairs (the circumferential speeds of the conveyance rollers 101 and 103) are set so as to satisfy the relationship expressed by the following mathematical expression (2).
second roller pair>first roller pair (2)
According to the relationship between the conveyance forces (mathematical expression (1)) and the relationship between the conveyance speeds (mathematical expression (2)), almost no slip is generated at the nip position of the first roller pair (between the conveyance roller 101 and the sheet S), which is a main conveyance unit. On the other hand, a slip is generated at the nip position of the second roller pair (between the conveyance roller 103 and the sheet S) due to a difference between the speeds.
In the configuration satisfying the above-described relationships, the first roller pair controls the conveyance accuracy as a whole of the printing unit 4. Between the first roller pair and the second roller pair, the sheet S is conveyed while being pulled toward the downstream side by the second roller pair operating at a higher conveyance speed. Therefore, a tension is applied to the sheet S to prevent the sheet S from locally floating, whereby a constant distance is kept between the print head 14 and the sheet S to maintain the high printing accuracy.
The pinch roller 102 of the first roller pair located upstream is divided into a plurality of (four) small rollers along the rotational axial direction (the vertical direction on the paper of
If the pinch roller 102 is constituted by a single roller body without being divided, even a slight inclination of the rotational axis, if any, results in an uneven distribution of the nip pressure applied to a sheet. This uneven distribution may cause a deviation of the sheet traveling direction from the originally set direction, i.e., a so-called skew state. Dividing the pinch roller 102 into a plurality of rollers allows the divided rollers to independently apply a nip pressure, thereby reducing the possibility that the nip pressure may be unevenly applied in the sheet width direction.
Further, a pinch roller constituted by a single body is subject to a deflection, and tends to intensively apply nip pressures at the respective edges of a sheet, whereby a difference is generated between the nip pressures at the respective edges to thereby destabilize force application to the sheet, facilitating generation of, for example, wrinkles, slacks, and a skew state of the sheet. The printing apparatus according to the present exemplary embodiment can use various sizes of sheets. Use of different sizes of sheets in the sheet width direction may cause the rollers located at the ends, among the plurality of divided rollers constituting the pinch roller 102 included in the first roller pair, to be put in the following three states in the rotational axial direction of the rollers: (1) a state that the roller is in contact with a sheet throughout the whole length of the roller; (2) a state that the roller is in contact with a sheet at only a part of the length of the roller; and (3) a state that the roller is totally out of contact with a sheet. It should be noted that the term “whole length” and “a part of length” here are used to mean the whole or a part of a generally linear narrow area at which a rotating roller contacts a sheet, but not to mean the whole surface of a roller throughout the entire circumference of the roller.
As will be used herein, the term “first roller portion” is used to refer to the outer rollers 102a and 102d farther away from the center of a sheet in the rotational axial direction, while the term “second roller portion” is used to refer to the inner rollers 102b and 102c located adjacent to the first roller portion and closer to the center of the sheet.
In the state (1) or (3), the outer rollers 102a and 102d rotate while keeping the same postures as the inner rollers 102b and 102c without being inclined. On the other hand, in the state (2), since the outer rollers 102a and 102d are partially in contact with the sheet S2, slight postural changes are made at the rollers 102a and 102d, leading to inclinations of the rollers 102a and 102 (refer to
In the state (2), the inclinations of the rollers 102a and 102d occur mainly in two directions. A first roller inclination occurs in such a manner that a portion of the roller rides on an edge of a sheet and is lifted up in the diametrical direction of the roller, thereby generating the inclination.
A second roller inclination occurs in the sheet conveyance direction. This inclination occurs as if a part of the roller in contact with a sheet is pulled by the moving sheet from the downstream side.
Generation of wrinkles and corrugations at a sheet, or generation of a skew state of a sheet during sheet conveyance leads to a deterioration of the quality of the image printed on the sheet. In view of this technical problem, the present exemplary embodiment provides a solution enabling sheet conveyance at high accuracy, no matter which sheet the printing apparatus uses. The present exemplary embodiment changes the difference or the ratio between the pressing force that the first roller portion applies to the conveyance roller 101 and the pressing force that the second roller portion applies to the conveyance roller 101 via the adjustment mechanism 110 according to a sheet that the printing apparatus uses. The concrete structure and operation for carrying out this operation now be described.
The four rollers 102a to 102d are held by four holders 154a to 154d respectively corresponding to the rollers 102a to 102d, and are arranged to be rotatable around a rotational shaft 112. Four plate members 113 are fixed to a common reference fixation portion 123 so as to respectively face the holders 154a to 154d. A rod 115 and springs, serving as elastic members, are disposed between each of the holders 154a to 154d and the corresponding plate member 113. The springs are constituted by three springs in total, a primary spring 114a disposed around the rod 115 as a helicoidal spring, and auxiliary springs (two springs) disposed at the both sides of the primary spring 114a. The three springs are arranged along the axial direction of the rotational shaft 112.
Cam mechanisms 150 are disposed at four positions as driving mechanisms for vertically moving the holders 154a to 154d, respectively. The cam mechanisms 150 each include a cam and a cam lever, and convert a displacement of the cam into a vertical movement of the cam lever. The rods 115 each have one end fixed to the tip of the cam lever, and the other end fixedly inserted through a hole formed at the holder 154a, 154b, 154c, or 154d so as to be prevented from being pulled out therefrom. The primary springs 114a each are compressed between the cam lever and the holder 154a, 154b, 154c, or 154d while being supported by the rod 115. Further, the auxiliary springs 114b each have one end fixed to the back surface of the plate member 113, and the other end fixed to the top surface of the holder 154a, 154b, 154c, or 154d, thereby being compressed there between. Since the auxiliary springs 114b are symmetrically disposed at the both sides of the primary spring 114a, even when the roller 102a, 102b, 102c, or 102d is about to be inclined, the auxiliary springs 114b can apply a force for preventing the inclination.
Vertically moving the cam levers by the cam mechanisms 150 causes vertical movements of the respective holders 154a to 154d through the rods 115. Each of the nip pressures of the rollers 102a to 102d is individually adjusted according to the position of the cam lever in the vertical movement direction and the sum of the spring pressures of the three springs 114a and 114b interposed in a compressed state.
In this structure, a rotation of the cam shaft 121 changes the phase of the cam 120, thereby changing the height of the cam lever 117. According thereto, the rod 115 is vertically moved, and thereby the holder 154 is vertically moved as well. As a result, the height of the pinch roller 102 is changed relative to the conveyance roller 101 having a fixed height, thereby allowing switching between the nip state and the release state. There is a difference between the phase of the cams 120 corresponding to the pinch rollers 102a and 102d, and the phase of the cams 120 corresponding to the pinch rollers 102b and 102c. Therefore, a rotation of the cam shaft 121 results in different vertical movements according to the pinch rollers.
The control unit 13 issues an instruction to drive the cam mechanisms 150 to change the distances of pressing the respective holders 154a to 154d via the primary springs 114a and the auxiliary springs 114b, which are elastic members, thereby determining the nip pressures. The pressing forces (nip pressures) with which the respective rollers 102a to 102d press the conveyance roller 101 can be changed according to the amounts of pressing the rods 115 (positions of the cam levers 117) by the cam mechanisms 150.
The printing apparatus according to the present exemplary embodiment switches the nip pressure to a suitable one to the condition (for example, the size and sheet stiffness) of a sheet that the printing apparatus uses.
The example 1 is the setting suitable to a sheet having a large size in the sheet width direction, and relatively high sheet stiffness. The term “large size” here means a size causing the outer two rollers 102a and 102d to be in contact with the both edges of the sheet throughout the whole lengths of the rollers 102a and 102d, as illustrate in
The example 2 is the setting suitable to a sheet having a middle size in the sheet width direction, and relatively high sheet stiffness. The term “middle size” means a size causing the outer two rollers 102a and 102d to be only partially in contact with the both edges of the sheet, as illustrated in
The example 2 is also the setting suitable to a sheet having a large size in the sheet width direction and relatively low sheet stiffness. Assume that the sheet size in this example is such a size that the both edges of the sheet extend further beyond the outer rollers 102a and 102d. If the sheet stiffness is lower than the example 1, the maximum nip pressures of the rollers 102a and 102d may cause the portions of the sheet extending beyond the rollers 102a and 102d to curve upwards. These portions, if they are large, may contact the print head 14. The example 2 sets the nip pressures of the outer rollers 102a and 102d to be lower than the inner rollers 102b and 102c, which is effective to prevent the edges of the sheet, which the rollers 102a and 102d cannot hold, from curving up.
The example 3 is the setting suitable to a sheet having a middle size in the sheet width direction and relatively low sheet stiffness. The adjustment mechanism 110 is set so that different forces, 200 gf, 1000 gf, 1000 gf, and 200 gf are applied to the four rollers 102a to 102d in this order. The total pressure of the nip pressures is 2400 gf. Since the sheet in the example 3 has lower sheet stiffness than the sheet in the example 2, although the sheet size is the same middle size, the total nip pressure is reduced compared to the example 2 to prevent the nip pressure from deforming the sheet. Different pressing forces are set for the inner rollers 102b and 102c, and the outer rollers 102a and 102d of the pinch roller 102, thereby preventing generation of wrinkles and corrugations at the sheet, and occurrence of a skew state of the sheet.
The example 4 is the setting suitable to a sheet having a small size in the sheet width direction. The term “small size” means such a size that the outer two rollers 102a and 102d are completely out of contact with the sheet, as illustrated in
The example 5 is the setting suitable at the time of rewinding of a sheet after a printing operation, or at the time of maintenance in response to occurrence of a sheet conveyance jam. All of the four rollers 102a to 102d are set so as to be floated from the conveyance roller 101 in a release state. All of the forces applied to the four rollers 102a to 102d are 0 gf. In other words, the total pressure of the nip pressures is 0 gf.
The above-described exemplary embodiments individually adjust the nip pressures according to a condition of a sheet that the printing apparatus uses, such as a sheet size and sheet stiffness. However, the nip pressures may be adjusted according to another condition of a sheet. For example, when the printing apparatus continuously prints data on both surfaces of a sheet as described above, at least one of the first roller portion and the second roller portion may apply different pressing forces to the conveyance roller 101 between printing on a first surface and printing on a second surface. Sometimes, the printing apparatus may have to print data under different sheet conditions between printing on a first surface and printing on a second surface. For example, a sheet with data printed on the first surface thereof is swollen by absorbing ink, and therefore the sheet stiffness of the sheet may be reduced at the time of printing on the second surface compared to the time of printing on the first surface. In this case, the adjustment mechanism 110 can be set in such a manner that the first roller portion and the second roller portion apply reduced nip pressures at the time of printing on the second surface compared to the time of printing on the first surface. Further, a sheet with an image printed on the first surface thereof may have a changed friction coefficient by absorbing ink. In this case, the nip pressures can be changed between printing on the first surface and printing on the second surface in consideration of the possibility of a slip. As a result, the printing apparatus can operate during printing on the first surface and printing on the second surface for two-sided printing under a same unchanged sheet conveyance condition, so that it is possible to reduce a positional misalignment between images printed on the front surface and the back surface of the sheet.
As described above, the exemplary embodiments of the present invention include the pinch roller 102 divided into a plurality of rollers including the first roller portion and the second roller portion adjacent to each other. Further, the exemplary embodiments include the adjustment mechanism 110 capable of changing the difference or ratio between the respective pressing forces which the first roller portion and the second roller portion apply to the conveyance roller 101. The pressing force of the first roller portion is changed according to the size of a sheet, which the printing apparatus uses, in the sheet width direction. Further, as a sheet to be used has lower sheet stiffness, the exemplary embodiments set the pressing force of the first roller portion to a weaker force. As a result, the exemplary embodiments can realize a sheet conveying apparatus and a printing apparatus capable of conveying a sheet at high accuracy regardless of a sheet that the printing apparatus uses.
As illustrated in
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures, and functions.
This application claims priority from Japanese Patent Application No. 2011-028715 filed Feb. 14, 2011, which is hereby incorporated by reference herein in its entirety.
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